1. Field of the Invention
The present invention relates to a battery system, and an electric vehicle, a mobile unit, an electric power storage device and a power supply device that include the battery system.
2. Description of the Related Art
In order to serve as a power source or electric power storage device for mobile units such as electric car, battery systems include a plurality of rechargeable battery modules. Each of the battery modules includes a plurality of batteries (battery cells) that are connected in series to each other, for example. Also, battery systems include a detection device that can detect abnormal conditions such overcharged and overdischarged conditions of battery cells.
A vehicle battery pack control device disclosed in Japanese Patent Laid-Open Publication No. JP 2003-79,059 A includes a plurality of simple cell-overcharge-and-overdischarge detection devices that are assigned to a plurality of cell groups in the battery pack. Each cell-overcharge-and-overdischarge detection device can determine whether the corresponding cell group is brought into an overcharged or overdischarged condition, and transmit the result to a battery controller.